1. Field of the Invention
The present invention relates to a gluing device, and more particularly to a gluing device usable in a corrugating machine for producing a corrugated paperboard sheet.
2. Description of the Related Art
Generally, a corrugating machine is designed to continuously produce a plurality of corrugated paperboard sheets from raw paperboards such as a corrugated medium and a linerboard. For this purpose, the corrugating machine is equipped with a gluing device for gluing or bonding a corrugated medium and a linerboard together. Examples of this type of gluing device include a gluing device used in a gluing machine to apply liquid glue to flute tip regions of a corrugated medium in a single-faced corrugated paperboard sheet in which the corrugated medium is bonded onto a planar linerboard.
The gluing device of the gluing machine comprises: a reservoir tank storing therein liquid glue; an applicator roll partially immersed in the liquid glue stored in the reservoir tank; a doctor roll for adjusting a thickness of the liquid glue adhered to the applicator roll to become uniform; and a pair of glue dams for regulating a width of the liquid glue adherable to the applicator roll. When the gluing device of the gluing machine is used in a situation where a width of a single-faced corrugated paperboard sheet used is greater than a width of a front linerboard, flute tip regions of a corrugated medium applied with the liquid glue are exposed in widthwise opposite edge regions of the single-faced corrugated paperboard sheet, thereby causing a problem that the liquid glue is wastefully used, and the exposed liquid glue adheres to a downstream-side heating plate.
With a view to solving this problem, for example, JP-U 04-094433A (Patent Document 1) discloses a gluing device for a gluing machine, wherein a pair of glue dams each movable in a width direction of a corrugated paperboard sheet are provided in a reservoir tank of the gluing device to thereby allow a transfer and supply width of liquid glue to be arbitrarily set in a variable manner, correspondingly to an effective crosswise width of a corrugated paperboard sheet to be produced.
Meanwhile, after the gluing, the resulting glued corrugated paperboard sheet is cut (slit) into a given width along a sheet feeding direction (machine direction) by a slitter apparatus disposed downstream of the gluing machine. The corrugated paperboard sheet after passing through the slitter apparatus is cut into a given cut length by a cutter apparatus disposed downstream of the slitter apparatus. A plurality of corrugated paperboard sheets cut by the cutter apparatus are sequentially stacked up to a given height by a stacker disposed on a downstreammost side of the corrugating machine.
In this process, a strip-shaped cutting scrap (hereinafter referred to as “trimming strip”) is formed along each of opposite edges of a corrugated paperboard sheet after passing through the slitter apparatus, because a width of an initial or original corrugated paperboard sheet is set to be greater than a cut width of the slitter apparatus. As illustrated in FIG. 12, such trimming strips 101 are sucked and collected by a suction duct 102 disposed along and downstream of a slitter apparatus 100. However, an increase in width dimension of each of the trimming strips 101 causes a problem that jamming-up (clogging) is more likely to occur inside the suction duct or around an inlet of the suction duct.
With a view to solving this problem, for example, JP 09-262790A (Patent Document 2) discloses a slitter apparatus, wherein, when a width of each trimming strip is greater than a given value, a cutting center of the slitter apparatus is offset in such a manner that a relatively narrow trimming strip and a relatively wide trimming strip are formed, respectively, in one of opposite edge regions of a corrugated paperboard sheet and in the other edge region, and wherein, when the relatively wide trimming strip has a width equal to or less than a given value, the relatively wide trimming strip is further narrowly cut, and then sucked and collected by the suction duct.